Ancient Calendars
Ancient calendars differ from the modern calendar in the way they calculate:
1) New years,
2) King years,
3) Months.
New Year and King Years
Different ancient calendars started the new year in different months.
Ancient peoples referenced the calendar year by stating how long a king had been in office. The calendars used two different methods to calculate a king’s first year.
1) Postdating: The king’s reign starts with year 0 (accession year) and can be as short as one day. The king’s 1st year starts at the New Year.
2) Predating: The king’s reign starts with year 1 and can be as short as one day. The king’s 2nd year starts at the upcoming New Year.
“[T]he Babylonian-Persian method was to postdate all reigns. That is, when a new king succeeded to the throne the scribes, who had been dating all kinds of documents by the day and month ‘in the 21st [or whatever] year of King X,’ would begin using the new dateline ‘in the accession year of King Y,’ and would wait until the next New Year’s Day to begin dating ‘in the year 1 of King Y.'”
——Julia Neuffer, The Accession of Artaxerxes I, Pages 60-61, Written 1968.
“Detailed checking of the source data has shown that the [Ptolemy] Canon uses two methods. In its earlier portion, which lists Babylonian and early Persian kings, it uses the postdating method (called by some the ‘accession-year method’). But in its latter portion, which lists the Seleucids and the Roman emperors, it antedates [predates] the reigns. That is, it counts as ‘year 1’ the year in which a king came to the throne, as if he had been reigning since the first day of the year. By this method, commonly used in Egypt, a scribe would begin dating in the king’s ‘year 1’ as soon as he came to the throne, and the first New Year’s Day would begin ‘year 2.'”
——Julia Neuffer, The Accession of Artaxerxes I, Page 61, Written 1968.
| Ancient Calendar | New Year | Modern | King Years |
|---|---|---|---|
| Hebrew | Nisan 1 | Mar/Apr | Either |
| Hebrew (civil) | Tishri 1 | Sep/Oct | Either |
| Babylonian | Nisannu 1 | Mar/Apr | Postdating |
| Persian | Nisannu 1 | Mar/Apr | Postdating |
| Egyptian | Thoth 1 | Dec (c. 460 BC) | Either |
Months
The Hebrew and Babylonian months start with the visible new moons and therefore do not match up exactly with modern months.
| Hebrew | Babylonian | Modern | |
|---|---|---|---|
| 1 | Nisan | Nisannu | Mar/Apr |
| 2 | Iyyar | Ajaru | Apr/May |
| 3 | Sivan | Simanu | May/Jun |
| 4 | Tammuz | Du’ûzu | Jun/Jul |
| 5 | Ab | Âbu | Jul/Aug |
| 6 | Elul | Ulûlu | Aug/Sep |
| 7 | Tishri | Tašrîtu | Sep/Oct |
| 8 | Marheshvan | Arahsamna | Oct/Nov |
| 9 | Kislev | Kislîmu | Nov/Dec |
| 10 | Tebeth | Tebêtu | Dec/Jan |
| 11 | Shebat | Šabatu | Jan/Feb |
| 12 | Adar | Addaru | Feb/Mar |
Ptolemy’s Canon
Ptolemy’s Canon, or the Canon of Kings, is a dated list of kings used by ancient astronomers to determine the timing of astronomical events, including eclipses. It serves as a foundation for ancient chronology and is a key component of the widely accepted chronology of the ancient Near East from 747 BC onwards. The dates listed in Ptolemy’s Canon have been supported by various sources, such as the Uruk King List, the Astronomical Diaries, and dated Egyptian papyri.